Ever lie to your parents, even once, about where you were after school? It’ll be tougher for today’s teenagers, who may have to leave their smart phones behind if they don’t want Mom and Dad following their every move. An increasing number of apps for mobile devices are utilizing GPS technology to help parents keep tabs on their kids. One research firm estimates that more than 70 million people across North America and Europe will be using such programs to track family members by 2016.

Skeptical? Some 20 million people have already downloaded Life360, a location app that allows family members to alert one another when they’ve arrived at various spots and to follow one another’s movements with by-the-minute updates. Jessica Denay, a single mother in Los Angeles, uses Life360 to monitor her 12-year-old son Gabriel as he travels to school, basketball practice and her ex-husband’s house. “I can’t even describe how comforting it is,” she says. “It’s hard for moms to let go of our babies. This makes me feel better. I don’t have to be hovering right there, but I know that he’s safe.”

Peace of mind aside, it’s not clear that electronic surveillance is the most effective way to parent in the digital age. “People have different styles of parenting and different notions of what it means to be on top of your children,” says Enrique Velasco-Castillo, a mobile analyst at IHS Screen Digest. “The problem is that many of these apps inadvertently send the wrong signal, saying, ‘I don’t trust you to tell me the truth of where you are and who [you are] with, so I will need to install this on your phone to track you.’ “

There’s also the question of compliance. While the monitoring apps can be effective with preteens getting their first smart phone, persuading rebellious teenagers to allow themselves to be tracked can be a bigger challenge. Mobiflock, a powerful Android app that allows parents to block the use of certain apps and even shut down cell-phone functionality remotely, has a bad rating in the Google Play store because kids have been loading it with one-star reviews. “It’s wack and won’t let me do anything and is blocking me from having a social life!” one (presumably teenage) user laments in an app review.

Life360 CEO Chris Hulls points out that parents’ demanding to know their children’s whereabouts is not a new development; teenagers have been rolling their eyes at this violation of their civil liberties for generations. And he tries to portray Life360 less as a surveillance device than as a tool for familial communication. “We don’t really see ourselves as a tracker,” he says. “It really is much more [centered] around family awareness. [The Life360 app] is just an easier and more efficient way of doing it.”

While Life360 controls much of the market, dozens of apps, offering a wide range of monitoring features, are available for parents interested in following their kids more closely. Here’s a look at some of the more popular among them:

Life360 (available for iPhone, Android, Windows Phone, BlackBerry; free): This hugely popular app offers a group-messaging program, the ability to “check in” at a location to alert family members that you’re there and safe, and of course GPS monitoring that can pinpoint a child’s location on a map for a worried parent. The map also marks the locations of hospitals, police stations and even the homes of registered sex offenders.

Securafone(available for iPhone, Android; free): This GPS-powered tracking app features a panic button that kids can press to immediately dial a number preset by the parent. It also has an Android-exclusive “distracted driver alert system” that disables the ability to text or use social media when the user is traveling faster than 5 m.p.h. Parents can also set up virtual fences around their kids — the boundaries of a school, for example — and be alerted when they exit the area.

SMS Tracker (available for Android; free): Once installed on a phone, this program runs in the background and allows a third party (like a nosy parent) to see all ingoing and outgoing call logs, text messages and photos. It’s already been downloaded more than half a million times.

Footprints (available for iPhone; $3.99 per year): As with Securafone, parents can set up virtual fences around their kids and be alerted when they exit the area. (This feature is said to be in development for Life360 as well.)

Mobiflock(available for Android, Nokia, BlackBerry; $25 per year): This app allows you to take complete control of your child’s phone from afar and block certain apps, disable the camera and even shut down phone functionality for a predetermined amount of time.